/*eslint-env amd */
define([
	'i18n!javascript/nls/problems',
	'module'
], function(ProblemMessages, module) {
	/**
	 * @fileoverview Rule to flag use of an object property of the global object (Math and JSON) as a function
	 * @author James Allardice
	 */

	"use strict";
	var stopNodePattern = /(?:Statement|Declaration|Function(?:Expression)?|Program)$/;


	//------------------------------------------------------------------------------
	// Rule Definition
	//------------------------------------------------------------------------------

	module.exports = function(context) {
		var props = context.options[0] && Boolean(context.options[0].props);

		/**
		 * Checks whether or not the reference modifies properties of its variable.
		 * @param {Reference} reference - A reference to check.
		 * @returns {boolean} Whether or not the reference modifies properties of its variable.
		 */
		function isModifyingProp(reference) {
			var node = reference.identifier;
			var parent = node.parent;

			while (parent && !stopNodePattern.test(parent.type)) {
				switch (parent.type) {

					// e.g. foo.a = 0;
					case "AssignmentExpression":
						return parent.left === node;

					// e.g. ++foo.a;
					case "UpdateExpression":
						return true;

					// e.g. delete foo.a;
					case "UnaryExpression":
						if (parent.operator === "delete") {
							return true;
						}
						break;

					// EXCLUDES: e.g. cache.get(foo.a).b = 0;
					case "CallExpression":
						if (parent.callee !== node) {
							return false;
						}
						break;

					// EXCLUDES: e.g. cache[foo.a] = 0;
					case "MemberExpression":
						if (parent.property === node) {
							return false;
						}
						break;

					default:
						break;
				}

				node = parent;
				parent = node.parent;
			}

			return false;
		}

		/**
		 * Reports a reference if is non initializer and writable.
		 * @param {Reference} reference - A reference to check.
		 * @param {int} index - The index of the reference in the references.
		 * @param {Reference[]} references - The array that the reference belongs to.
		 * @returns {void}
		 */
		function checkReference(reference, index, references) {
			var identifier = reference.identifier;

			if (identifier &&
				!reference.init &&

				// Destructuring assignments can have multiple default value,
				// so possibly there are multiple writeable references for the same identifier.
				(index === 0 || references[index - 1].identifier !== identifier)
			) {
				if (reference.isWrite()) {
					context.report(
						identifier,
						ProblemMessages.noParamReassign,
						{
							name: identifier.name
						});
				} else if (props && isModifyingProp(reference)) {
					context.report(
						identifier,
						ProblemMessages.noParamPropertyReassign,
						{
							name: identifier.name
						});
				}
			}
		}

		/**
		 * Finds and reports references that are non initializer and writable.
		 * @param {Variable} variable - A variable to check.
		 * @returns {void}
		 */
		function checkVariable(variable) {
			if (variable.defs[0].type === "Parameter") {
				variable.references.forEach(checkReference);
			}
		}

		/**
		 * Checks parameters of a given function node.
		 * @param {ASTNode} node - A function node to check.
		 * @returns {void}
		 */
		function checkForFunction(node) {
			context.getDeclaredVariables(node).forEach(checkVariable);
		}

		return {
			// ':exit' is needed for the 'node.parent' property of identifier nodes.
			"FunctionDeclaration:exit": checkForFunction,
			"FunctionExpression:exit": checkForFunction,
			"ArrowFunctionExpression:exit": checkForFunction
		};

	};

	module.exports.schema = [{
		type: "object",
		properties: {
			props: {
				type: "boolean"
			}
		},
		additionalProperties: false
	}];

	return module.exports;
});